Class MaybeQueryInterceptor

Namespace

Trellis.EntityFrameworkCore

Assembly

Trellis.EntityFrameworkCore.dll

An EF Core query expression interceptor that automatically rewrites Maybe<T> property accesses in LINQ expression trees to their underlying storage member equivalents.

public sealed class MaybeQueryInterceptor : IQueryExpressionInterceptor, ISingletonInterceptor, IInterceptor

Inheritance

object

MaybeQueryInterceptor

Implements

IQueryExpressionInterceptor

ISingletonInterceptor

IInterceptor

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Extension Methods

MaybeExtensions.AsMaybe<T>(T)

AggregateTestMutator.ClearMaybeField<TEntity, TValue>(TEntity, Expression<Func<TEntity, Maybe<TValue>>>)

AggregateTestMutator.SetMaybeField<TEntity, TValue>(TEntity, Expression<Func<TEntity, Maybe<TValue>>>, TValue?)

Examples

With this interceptor registered, these LINQ expressions work directly:

// Natural LINQ — no explicit extension methods needed
context.Customers.Where(c => c.Phone.HasValue)
context.Orders.Where(o => o.SubmittedAt.GetValueOrDefault(DateTime.MaxValue) < cutoff)

// Specifications with Maybe<T> properties
public override Expression<Func<Order, bool>> ToExpression() =>
    order => order.Status == OrderStatus.Submitted
          && order.SubmittedAt.GetValueOrDefault(DateTime.MaxValue) < _cutoff;

Remarks

When registered, this interceptor allows natural LINQ syntax with Maybe<T> properties in queries and specifications, without requiring explicit extension methods like WhereHasValue or WhereEquals.

Register by calling optionsBuilder.AddTrellisInterceptors() — that helper installs both this interceptor and the companion Trellis.EntityFrameworkCore.MaybeEvaluatableExpressionFilterPlugin required for correct c.Maybe == Maybe.From(value) translation. Registering only the interceptor via optionsBuilder.AddInterceptors(new MaybeQueryInterceptor()) is sufficient for the rewrite patterns listed above, but leaves natural-form equality against Maybe.From(value) silently translating to _field IS NULL.

Methods

QueryCompilationStarting(Expression, QueryExpressionEventData)

Rewrites the query expression tree before compilation, replacing Maybe<T> property accesses with EF Core-translatable storage member references.

public Expression QueryCompilationStarting(Expression queryExpression, QueryExpressionEventData eventData)

Parameters

queryExpression Expression

eventData QueryExpressionEventData

Returns

Expression